ANN Flies The Eclipse 500... and The Eclipse Lives (Part 6 of
7)
By ANN Editor-In-Chief Jim Campbell
An initial climb to 15,000 feet, to a test area South of ABQ,
and slightly retarded throttles (about 90%) produced about 670 pph,
while I sampled the overall feel and investigated each axis of
control.
In speeds of 150-200 knots, pitch proved itself to be a fairly
steady customer, typified by well defined static properties and a
fairly tight dynamic response throughout the envelope… short
period investigations were quite obedient, tightly defined and
virtually deadbeat in response. Roll offers light adverse yaw,
moderate to heavy forces and an agile response. The roll rate is
solid (no problem cranking out 30 degree per second rates) while
repetitive 45 to 45 degree rolls and 60 to 60 degree rolls offered
obedient response (especially if led with just the tiniest touch of
rudder).
Laterally, the aircraft boasts very good roll stability and the
spiral attributes were very docile… a bit of a surprise,
that. There is a modest but increasing force gradient through the
120-230 kt speed range that is perceptible but never ponderous. It
serves as an excellent indicator of aircraft state (it doesn't take
much to figure out your speed by the nature of the feel) but rarely
interferes with aircraft harmonies.
At 200 knots, I was invited to start abusing the E-500 a mite in
order to get a sense for how hardy Vern was trying to make his
little jet. Gear extensions were initiated at all of 200 knots, the
planned gear extension limit, and the sensation was altogether
predictable. The aircraft pitches up a mite (mostly due to the
manner in which the nosegear deploys, Vern tells me), but the
somewhat less than energetic (though I am apparently the only one
who feels that way) pitch trim stays up with the new pitch attitude
eventually and the effect is rather sedate. The gear is draggy, but
not quite the anchor I expected. Once deployed, there is only a
slight change in cabin noise - which I found (throughout the
flight) to be fairly mild.
Slam That Throttle
I was invited to do a series of throttle slams, both together
and asymmetrically. At 200 knots, the PW's spool down modestly, and
the aircraft's limited mass/inertia displays the loss of thrust
with a slight pitch positive response and a notable deceleration.
Slam those throttles forward and you are rewarded with a very
notable acceleration, a slight pitch negative transition, and a
spool time that took about 5 seconds to get it's act
together… faster than I expected from the teeny turbines.
Asymmetric throttle reductions were expected to be a non-event
after my single-engine work the year before in a simulator based on
the flight test model (developed from the original prototype). Mind
you, at 200 knots, we're not expecting big trouble, but the fact
that I could keep my feet flat on the floor and only bank a mite to
counter the dissymmetry was promising. Vern wants really docile
single-engine handling, and the current data suggests he may get
his wish… we look forward to far more aggressive trials when
the flight test parameters are opened up a bit more.
Runs to 230 knots (the current operational limit) produced no
surprises and few overt differences from the operations we'd
conducted at 200 knots-fuel burns were well under 770 pph, up a bit
from 630 pph at 200k and the 400 or so we used at 150k. Mind you,
these numbers are pretty much worthless from an operational
standpoint-very little of the Eclipse's operational imperative will
be realized at the 15-18K altitudes we played in and the aircraft
is still awaiting some aerodynamic refinements that should offer
additional efficiencies. The Eclipse was bred to fly high, where
the weather is usually far below and the fuel burns are
miserly… but from what I can see of the profile thus far,
the predictions for future Eclipse fuel requirements are not
unrealistic.
The Bottom End Of The (Temporary) Envelope
Our mission plan did not call for actual stalls on this flight
since a stall/spin chute was not attached to this aircraft while
that chore was about to be undertaken by a different test aircraft.
Our bottom limit was 85 knots but there were no prohibitions in
that regime… I was free to play with it all that I liked. At
85 knots, I ran out of aft pitch trim, but the remaining pressures
were not all that difficult to comply with.
In decelerating for the slow flight series, I noted that flap
extension seemed to trim pitch up with the first (Takeoff) notch of
flaps, slightly negative with the second (Approach) notch and was
only a little more so with the last notch (Landing). That last
notch produces quite a bit of drag and an eventual sweet spot,
speed-wise, that is quite predictable and dependable when flown at
all of 85-100 knots. Overall control remains agile, rates change
little, the forces are notably diminished… (but never to the
point of getting truly light) and the aircraft's stability profile
seems barely affected. This is particularly pleasing in both pitch
and roll-while yaw does tend to get just a bit less defined,
statically, than previously noted-though the coupling
characteristics we noted earlier remained quite aggressive. I was
allowed considerable latitude in this regime, even to the point of
a number of successive 60 to 60 degree roll reversals and a fair
amount of rapid control input (hint: this is otherwise known as
goofing around). The bird feels quite nice here and is never
threatening.. and is a far bit nicer than a lot of piston twins at
this speed (the E-500 puts the Aerostar to shame in this speed
regime and kicks a P-Baron's keister all over town). Unfortunately;
while screwing around, I did manage to tumble the AHRS (those of
you who have accused me at various times of being unbalanced now
have your proof… I'll go quietly) and threw my PFD off its
rocker… making my attempt to shoot a quick ILS on the right
hand PFD a fairly comical affair (though not nearly as bad I
feared). Terry only grimaced once or twice and didn't giggle even
once. Tough guys, those USAF pilots. Fearless, too.
With slow-flight proving to be of limited challenge (even to
yours truly), it was time for the ultimate test… letting me
land the Eclipse. While eying the Southwest 737s clobbering the
runway below, I felt confident that the runway was strong enough
for my usual mode of landing (often compared to a carrier approach,
my friends tell me… though I hope they're talking about my
'impeccable' spot landing accuracy and NOT my usual descent
rate… hmmm).
I flew a number of standard patterns to Runway 8 and then to Rwy
3, feeling fairly comfy even when required to play with tighter
patterns and closer quarters in order to make way for Uncle Boeing.
At this point… over an hour after our departure, I was
feeling very cool with the Eclipse.
To Be Continued
ANN's Daily Aero-Term (04.14.24): Maximum Authorized Altitude
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